1. Field of the Invention
The present invention relates to an electronic component having an active element and a passive element that are resin-sealed to a substrate, and to a method for manufacturing the same. In particular, the present invention relates to an electronic component that is highly reliable both electrically and structurally, and to a method for manufacturing the same.
2. Description of the Related Art
As a conventional electronic component of this type, a high-frequency semiconductor device disclosed in Japanese Unexamined Patent Application Publication No. 2003-124435 (Patent Document 1), and a high-frequency module and method for manufacturing the high-frequency module disclosed in Japanese Unexamined Patent Application Publication No. 2002-033419 (Patent Document 2) are known.
In the high-frequency semiconductor device according to Patent Document 1, a composite resin material layer composed of epoxy resin and an inorganic filler is provided on a lower surface of a ceramic substrate. A lower portion of the composite resin material layer is flat and is provided with an external-connection-terminal electrode. The composite resin material layer has implanted therein semiconductor elements and passive elements, which are connected to the ceramic substrate. Accordingly, as an all-in-one module package of a send/receive system, the high-frequency semiconductor device achieves compactness and high-density packaging.
On the other hand, the high-frequency module according to Patent Document 2 is provided with a high-frequency circuit portion including electronic elements disposed on a substrate, and a shielding film for electromagnetically shielding the high-frequency circuit portion. The high-frequency module is also provided with a resin mold layer within which the electronic elements are enclosed. The shielding film is a metallic film disposed on a surface of the resin mold layer. Thus, a designated shielding member is not necessary.
In Patent Documents 1 and 2 described above, active elements, such as semiconductor elements and integrated circuit chips, and passive elements, such as capacitors and resistors, are all disposed on one side of a ceramic substrate such that the active elements and the passive elements are enclosed within a resin layer.
However, the conventional electronic component, such as the high-frequency semiconductor device and the high-frequency module, is problematic in that electromagnetic mutual interference occurs between the active elements and the passive elements because the active elements and the passive elements are all disposed within the resin layer on one side of the ceramic substrate. Moreover, in the conventional technology, the active elements and the passive elements disposed on the ceramic substrate are set within the resin layer by heat curing a thermosetting resin material. This produces a significant change in the volume of the resin layer with respect to the ceramic substrate before and after the heat curing process, thus increasing a possibility of, for example, delamination between the ceramic substrate and the resin layer. Even if such delamination is not produced, the significant change in volume may cause structural defects in the ceramic substrate, such as cracks and breakages.